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Thread: Embryo-free techniques for deriving stem cells

  1. #1

    Embryo-free techniques for deriving stem cells

    Gretchen Vogel of Science Magazine reports from the June 2005 meeting International Society for Stem Cell Research in San Francisco:

    According to Vogel, "many scientists believe that sometime in the coming decade, they will know enough about cellular 'reprogramming' to bypass some of the steps required today" to induce transformation directly without the need for embryos or oocytes. Specifically, the following work reported at the meeting was relevant (by the way, I was at this meeting and missed these talks):

    • Kevin Eggan used human embryonic stem cells to "reprogram" gene expression of human fibroblasts (skin cells), to create pluripotent stem cells that contain the genes of the fibroblasts. They used polyethylene glycol (PEG) to fuse embryonic stem cells with skin cells. The cells are tetraploid (having four chromosomes) but cultured, they behave like pluripotent embryonic stem cells. Eggan is part of the Melton group at Harvard. They are finding out that when an embryonic stem cell fuses with a somatic cell, the fused cell is often a stem cell. The open question is whether the genes of the embryonic stem cells can be removed now without altering the pluripotency of the cells. By the way, this work was done with human lines developed by Doug Melton without any NIH funding.

    • Markus Grompe from OHSU in Portland Oregon proposed that over-expressing a stem cell gene called Nanog in an egg or a somatic cell, and fusing the two cells may result in the direct production of embryonic stem cells without the formation of a blastocyst or pre-embryo. According to Vogel in this article, this idea has been endorsed by a number of conservative bioethicists, including Tadeuzz Pacholcyk (a strong opponent of embryonic stem cell research involving the harvesting of embryonic stem cells from blastocysts).

    In the meantime, of course Representative Roscoe Bartlett (R-MD) has been pushing hard for these versions of creating stem cells without embryos. He advocates appropriating funding for animal studies to test these and other ideas. Senator Rick Santorum (R-PA) who is adamantly opposed to any use of embryos for research supports this funding.


  2. #2

    How scientific advances are outstripping policy and legislation

    In an earlier Science article, Gretchen Vogel explored the concept of how egg cytoplasm reprograms a nucleus to think that it is an egg cell. Markus Grompe's idea is particularly interesting here. Many laboratories are now trying to find what is in egg cytoplasm that reprograms a nucleus to think that it is an egg cell. It is likely that they will find what is in egg cytoplasm that does this and then if they express a stem cell gene such as Nanog in the cell, they would be able to go directly from somatic cell to embryonic stem cells without having involve eggs or embryos.

    One of the reason why I have been posting these articles is because they are now reflecting a startling shift in scientific attitudes towards embryonic stem cell. Although I have been saying for some time on these forums that an embryonic stem cell is merely a cell that is expressing certain genes and that it should be possible to make any cell into a stem cell, I was just speculating. Now scientists are seriously working on this and making a startling progress. In the past week, we have heard about eggs derived from bone marrow and even skin cells. It would not surprise me at all if by the next International Society for Stem Cell Research meeting, we will hear scientists reporting that they have made somatic cells behave like embryonic stem cells.

    I sincerely hope that these developments will reassure opponents of embryonic stem cell research that scientists don't have a penchant to harvest stem cells from embryos and that there is no slippery slope here. On C-span last night, I listened a group of staunch anti-embryonic stem cell legislators, including Mike Ferguson (R-NJ), Chris Smith (R-NJ), Michael Burgess (R-Texas), Roscoe Bartlett (R-MD), Rick Santorum (R-PA), and others express the fear that passage of HR810 will lead to millions of embryos being used to create stem cells. I think that their fear is not well-founded.


  3. #3
    There is a correction that needs to be made to Vogel's article. The Conservative Bioethicists have given these methods conditional, tentative support. If they can be shown to be effective in animals (without creating embryos), they will support testing the then proven method(s) in humans.

    The concensus among Conservative leaders I have spoken with has been that cellular reprogramming (dedifferentiation/transdifferentiation) has the most promise.

    Of interest, one of the methods Grompe is proposing (overexpressing Nanog in oocytes prior to nuclear transfer) is an example of what William Hurlbut is proposing: Oocyte Assisted Reprogramming (OAR).'s worse than we thought. it turns out the people at the white house are not secret muslims, they're nerds.

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